Utilities

Google Guava inspired LRU cache. [Reference: Google Guava](https://code.google.com/p/guava-libraries/]. In-memory LRU cache implementation for Node,
inspired by Google Guava Loading Cache . The cache is simpler since it doesn't have to deal with concurrent threads, but other functionality of Guava
cache are captured like

- A data structure that uses a single, fixed-size buffer as if it were connected end-to-end.
When the buffer is filled, new data is written starting at the beginning of the buffer and overwriting the old.